368 THE OUTGO OF ENERGY 



twice every second, keeping time with the beat of 

 a metronome, until two hundred contractions 

 have been made. 



Now stimulate artificially every two sec- 

 onds, using maximal make and break currents 

 alternately, until two hundred contractions have 

 been made. 



State the characteristics of the two fatigue 

 curves, and compare the curves with those 

 obtained from frog's skeletal muscle. 



2. From a fresh subject obtain a fatigue curve 

 by artificial stimulation of the abductor indicis, 

 using maximal make and break induction cur- 

 rents alternately every two seconds, as directed 

 in the preceding experiment. When the muscle 

 has been stimulated two hundred times, contract 

 it voluntarily every two seconds until two hun- 

 dred contractions have been made. 



Compare the curves with those obtained in 

 Experiment 1. 



Explain these paradoxes. 



It has been pointed out on page 357 that 

 smooth muscle loses its irritability much more 

 rapidly than striated muscle. 



APPARATUS 



Normal saline. Bowl. Towel. Pipette. Glass plate. 

 Volume tube. Bunsen burner. Inductorium. Two dry 



